Relief-valve for air-compressors.



Patented Nov; 25, |902. A. GIESLER.

RELIEF VALVE FUR AIR GOMPRESSUHS.

` (Application filed Mar. 27, 1901.) (No Model.)

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NITED l STATES;

PATENT OFFICE.

ARTHUR GIESLER, OF DAYTON, OHIO, ASSIGNOR TO THE STILWELL-BIERCE l da SMITH-VAILE COMPANY, OF DAYTON, OHIO, A CORPORATION OF NEW JERSEY.

SPECIFICATION forming part 0f Letters Patent No. 714,295, dated. November 25,` 1902.

` Application led March 2,7, 1901. Serial No. 53,018. (No model.)

Bet knownthat I, ARTHUR GIEsLER, a citizen of the United States, residing at Dayton, in the county of Montgomery and State' of Ohio, have invented certain new and useful Improvements inRelief-Valves for Air-Compressors; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art tol which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

My invention appertains to air-compressors, and comprises means for unloading the compressor at times when the air is not used or is used in diminished quantities. The air compressor, say, is driven by steam, and, for example, it is furnishing air for a mining plant to drive rock-drills. As long as the drills are working all the air furnished by the compressor, comparatively speaking, is being consumed; but as soon as one or more of the drills is stopped and the compressor is not stopped an accumulation of the air in the airreceiver will go on, and consequently the pressure in the air-receiver will rise higher than the normal pressure, which may be from eighty to one hundred pounds. The compressor in such case will blow od into the atmosphere, and thus all the power consumed by the air-compressor is wasted. In mining plants the air-compressor is usually located considerable distance from the work-for eX- ample, a mile or more-and when the drills are stopped such stoppage takes place while the air-compressor is furnishing the necessary air-in other words, the work of the compressor goes on.

My invention comprises means that enables the compressor to continue running after the drills are stopped, and this continued running of said compressor does not require any more power than is necessary to run the compressor empty. This is done by means of an unloading or relief device, which delivers the compressed air from the front of the com7 pressor-piston and to the back of the same alternately, thus equalizing the pressure on both sides of said piston. Consequently it will take no more power to drive the piston than is necessary to overcome the ordinary friction. The compressor-piston in such case is not worked against the load and is partly balanced.

Preceding a detail description of my invention, reference is made to the accompanying drawings, of which- Figure l is an elevation of the compressorcylinder and a portion of a receiving-tank, the valve mechanism being shown connected up. Fig. 2 is an enlarged section on the line z .e of Fig. 1. Fig. 3 is a sectional view on the line y 'y of Fig. l. Fig. 4c is a sectional view on the line m x of Fig. 2. Fig. 5 is an enlarged vertical sectional view of the relief or unloading valve. e

A designates a portion of a compressor-cylinder, and B a portion of the piston therein.

It has notvbeen thought necessary to illustrate any more of the apparatus than is sufficient for the purpose of an explanation of my improvement, which is placed in an integral part of the comressor-cylinder and consists of two valvesD and D,which are inclosed in cas-` ings C C at each end of the comrpessor-cylinder. These valves D and D open outwardly from the compressor-cylinder and admit air through ports G" into the compressor-cylinder. The stems E and E thereof have at their upper ends pistons F and F. The said valves and pistons are placed in inner casings C and 0". The stems E and E/ pass through guides G and Gr', which are seated on shoulders a in the inner casings and are maintained in such positions by the coilsprings b and b, which surround the valvestems and are inclosed between the pistons F and F' and guides G G. Y

H H designate valve covers.. Between these covers H H and the valve-casings C C there are inclosed leather or rubber diaphragms e e', which diaphragms are also secured to the upper ends of the pistons.` There is a suitable space vl between thecovers and the pistons which enables the diaphragms to move up, the edges of said diaphragms being held securely between the covers and the valve-casings. The dotted lines show the IOO positions of such diaphragms when the valves D and D are lifted from their seats. By means of these diaphragms e e', placed above the pistons in the manner shown, all possibility of any passage-of air from above or below the pistons is obviated. This is an important feature of my invention and one which renders the same a practical success.

H designates hand-wheels, which are secured to screws H3, passing through the valvecovers H and H. These hand-wheels and screws afford means for locking the valves D D on their seats whenever it vbecomes necessary to place the deviceoutofan operatingcondition. These adjusting-screws also serve to regulate the movement of the valves, and thereby relieve the diaphragm e of the strain which is due to the opening of the valves. By turning the hand-wheels the screws may be brought in contact with the diaphragme on the pistons, and thus hold the valves in their seats, and vice versa.

I is an air-channel which communicates with the ends of the compressor-cylinder at such times as the valves D D are open and through which air is admitted alternately on both sides of the compressor-piston B.

J designates a relief or unloading valve, between the median portion of which and the upper ends of the pistons F F a communication is established through pipes K K. Valve J has two seats c c', one of which the piston J seats against in its downward movement and the other of which it seats against in its upper movement. As shown in the drawings, the said valve is closed against its upper seat c by means of a weight W. In this condition of the valve the compressor is compressing air and such air is being consumed by the Work performedfor example, the rock-d rills. The unloading or relief device is at this time idle. When such device is in operation, the weight W is elevated to lift the piston J from its seat c, at which time the lower seat' c is closed. The end valves D D are elevated to allow a communication between the airchannel I and the ends of the compressorcylinder. In this movement of said valves the diaphragrns e c are raised against the covers H H', and such valves have the necessary opening. Air is prevented from passing above the pistons F F by the diaphragms c e'.

L L are bolt-holes by means of which the unloading or relief valve J is secured to the compressor. The relief-valve J is placed on the side of the compressor-cylinder and, as before stated, is connected with the end valves D D through pipes K K.

The weight lW balances the air-pressure from the receiver against the under side of the valve-piston J and holds said piston down on the upper seat c. This will hold said piston J down from the seat c', and thus admit air under receiver-pressure into the pipes K and K and above the pistons F and F. This pressure will then hold the valves D D closed, it being strong enough to compress the springs b b. If the demand for compressed air should be below the amount furnished by the compressor and thus cause the pressure to rise above the normal pressure for which the valve is set, this higher pressure on the bottom of the piston J will then lift and will first' allow the valve to close the opening c,thereby cutting off all communication between the air-receiver and the valves D DE The piston J by being lifted farther will open the valve at c and allow the compressed air back of the pistons on the valves D and D to escape through the holes ol d. The sp rings h b will now open both of such valves, so that the air confined in the compressor-cylinder instead of being compressed in the end M of said cylinder passes through the valve D,:the channel I, and the valve D into the other end M 0f said cylinder, and vice versa. When the pressure in the receiver falls back to the normal pressure, the

weight W will cause the piston J to lower, first closing the valve at c and next lowering said valve from the seat c. At this time there is free communication between the airreceiver and the back of the pistons on valves D D', thus allowing the receiver air-pressure to close said valves D Di The piston or compressor will again operate and compress air as before.

As shown in the drawings, both the valves D and D are closed and the unloading or relief valve J is closed against its upper seat c by the weight W. The machine in this condition is compressing air. When the compressor is operating, but not furnishing air for work, the accumulation of air in the receiver will cause pressure in the relief-valve through the pipe N and will cause the piston J to seat against the lower seat c. This will shut off receiver-pressure from the pipes K and K. The diaphragms e e will then be raised to the dotted lines by the action of the pistons F and F.

Having described my invention, I claiml. In an air-compressor, two cylindrical valve-casings connected by an air-channel and located one at each end of the compressorcylinder, ports leading from the lower ends of the casings to the corresponding ends of the cylinder, valvesin the casings, commanding the ports and opening outwardly, springs for opening said valves, pistons upon the valve-stems, diaphragme secured to the pistons and to the cylindrical casings, a chamber in the upper ends of said casings above the diaphragms, a valve-casing located at the side of the compressor, and containing two oppositely-facing valve-seats, passages through said seats connecting the ends of the casing with the space between the seats, valves for the passages so arranged that one is seated as the other is unseated, an airvent in one end of the casing, means for holding the valve commanding the vent normally seated, and the other one open, a pipe connecting the compressor reservoir with IOO IIO

l IO

theclosed end of the casing, and pipes connecting the space between the valves with` the chambers above the diaphragms.

2. In a compressor, the combination with a cylinder, of a valve located at each end Aof said cylinder,a passage communicating with* the' ends of said cylinder and controlled by said valves, each of said valves having apiston located on the end thereof, a diaphragm secured to said piston and movable in a `chamber thereabove, a cap forming the upper inclosure of said chamber and by means of which the diaphragm is secured to the casing,A a screw penetrating said cap above the piston and by means of which the movet ment of the valves may he regulated or the said valvesmay be locked on their seats, a

spring surrounding the valve-stemand by `means of which the valve is removed from its seat when the diaphragm is relieved of pressure, a relief-valve, a receiver-pipe communicating with said relief-valve, and pipe connections between said reliefvalve and the `chambers above the diaphragms, substantially as set forth. 3. In an air-compressor, the combination `with a compressor-cylinder, a piston-valve located at each end of said cylinder, an airpassage communicating with the ends of` said cylinder and controlled by said valves, a spring surrounding the stem of each of said pistonvalves and serving to open said valves when relieved of their closingpressure,- a diaphragm secured to said piston-valves, an

adjusting screw above said diaphragm by means of which said valves are limited in their movement, a cap above said valves through which said adj ustingscr|ew penetrates, said cap having its inner surface hollow to provide a chamber for the movement of the diaphragm, a double-seating reliefvalve, pipe connections between said relief- ARTHUR `emsLER.`

Witnesses:

J. A. WORTMAN, t R. J. MCCARTY. 

